Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, Illinois 60607, USA.

Abstract

The occurrence of groundwater in Antarctica, particularly in the ice-free regions and along the coastal margins is poorly understood. Here we use an airborne transient electromagnetic (AEM) sensor to produce extensive imagery of resistivity beneath Taylor Valley. Regional-scale zones of low subsurface resistivity were detected that are inconsistent with the high resistivity of glacier ice or dry permafrost in this region. We interpret these results as an indication that liquid, with sufficiently high solute content, exists at temperatures well below freezing and considered within the range suitable for microbial life. These inferred brines are widespread within permafrost and extend below glaciers and lakes. One system emanates from below Taylor Glacier into Lake Bonney and a second system connects the ocean with the eastern 18 km of the valley. A connection between these two basins was not detected to the depth limitation of the AEM survey (∼350 m).

(a) Map of major lakes, glaciers and DVDP boreholes in Taylor Valley, Antarctica. Dotted red line indicates the location of the Lake Fryxell DVDP geophysical survey () (b) AEM flight lines in green with survey lines for which data were processed shown in yellow. Terrain surveyed in this paper is highlighted in red. Dashed line indicates regions where higher-resolution surveys were conducted in the Bonney () and Fryxell Basins (). Red circle indicates the location of the example SkyTEM sounding ().

Resistivity profile along the length of the Taylor Valley (flight line denoted in red in ). Low resistivities near McMurdo Sound to Lake Hoare interpreted as hydrological connectivity of brine in sediments extending from the coastal margin inland and beneath the Canada Glacier. To the west, resistivities increase below Suess Glacier and again towards Lake Bonney. In the Bonney Basin, low-resistivity patterns suggest connectivity of brine-rich sediments below the Taylor Glacier with proglacial Lake Bonney at the glacier terminus and near the location of Blood Falls.

(a) Photograph of the Lake Fryxell Basin survey area with the profile line indicated in black. McMurdo Sound is to the east (b) 3D presentation of resistive glacier ice and permafrost with conductive lake water and brine-saturated sediments. (c) Lake Fryxell Basin image from b with resistivities above 100 Ωm removed to show the spatial extent of conductive brine-saturated sediments.